Spinal Accessory Nerve

Cranial nerve XI has a cranial portion (4 to 16 rootlets) and a spinal portion (6 to 7 rootlets) from C1 to C6 dorsal to the dentate ligament. The cranial and spinal portions of CN XI

enter the vagal meatus together; however, they may infrequently be separated by a dural septum. Cranial nerve XI may be indistinguishable from CN X in the jugular foramen. After exiting the foramen, CN XI descends obliquely and laterally between the ICA and internal jugular vein, and then posteriorly across the lateral surface of the vein to reach the stern-ocleidomastoid and trapezius muscles. In 30% of specimens, CN XI descends alternatively on the medial surface of the internal jugular vein.2

0 0

Post a comment